Microcondenser device

ABSTRACT

A microcondenser device for an evaporative emission control system associated with an internal combustion engine includes a housing having a lower wall and at least one side wall extending upward from the lower wall. The lower wall and the at least one side wall together defining a chamber in the housing. A thermoelectric element is supported by the at least one side wall in spaced relation relative to the lower wall. An inlet is defined in the housing for admitting fuel vapor into the chamber. A condensation outlet is defined in the housing for discharging liquid fuel that is condensed from the fuel vapor in the chamber. A porous heat sink element is received in the chamber for absorbing the fuel vapor admitted through the inlet. The porous heat sink element is in conductive thermal contact with the thermoelectric element.

BACKGROUND

The present disclosure generally relates to evaporative emission controlsystems for internal combustion engines, and more particularly relatesto a microcondenser device for an evaporative emission control systemassociated with an internal combustion engine.

Conventional vehicle fuel systems associated with internal combustionengines typically employ a fuel canister for receiving fuel vapor from avehicle's fuel tank. The fuel canister is adapted to temporarily retainthe received vapor therein to prevent it from being released to theatmosphere. More particularly, fuel vapor can enter the fuel canisterfrom the fuel tank wherein the fuel vapor is absorbed and retained in acarbon bed of the fuel canister. Typically, the retention of thedisplaced fuel vapor within the fuel canister is only temporary as thefuel vapor retained in the fuel canister is periodically purged to allowthe canister to accommodate and absorb additional fuel vapor from thefuel tank. During such purging, the fuel vapor captured by the canistercan be sent to the vehicle's engine, and particularly to an inductionsystem of the engine, for combustion.

Various other systems have been proposed to more strictly controlcontainment of fuel vapors and/or improve vehicle efficiency bycontrolling fuel vapor processing. For example, some systems include abladder disposed in the vehicle's fuel tank that expands and contractsto control fuel vapor. A pump can be used in association with thebladder for applying pressure to the walls of the bladder. The pressureis applied for purposes of forcing the bladder walls against the fuelcontained therein to prevent or limit vapor formation. A fuel canister,as described in the preceding paragraph, can optionally be used in thebladder fuel system for capturing fuel vapor that forms despite the useof the bladder.

Also known is a canisterless evaporative emission control system for aninternal combustion engine. One particular known system includes a fueltank wherein vaporized fuel is generated and a microcondenser device forprocessing the vaporized fuel received from the fuel tank. Themicrocondenser device has a heat sink portion formed of carbon foam inthermal communication with a thermoelectric element for removing heatfrom the heat sink portion. The fuel vapor is processed by passing thefuel vapor through the heat sink portion to remove heat therefrom andcondense at least a portion of the fuel vapor to liquid fuel. Drawbacksof this known canisterless control system include significant powerconsumption requirements for the thermoelectric element and asignificant volume of uncondensed fuel vapor passing through themicrocondenser device.

SUMMARY

According to one aspect, a microcondenser device is provided for anevaporative emission control system associated with an internalcombustion engine. The device includes a housing having a lower wall andat least one side wall extending upward from the lower wall. The lowerwall and the at least one side wall together define a chamber in thehousing. A thermoelectric element is supported by the at least one sidewall in spaced relation relative to the lower wall. An inlet is definedin the housing for admitting fuel vapor into the chamber. A condensationoutlet is defined in the housing for discharging liquid fuel that iscondensed from the fuel vapor in the chamber. A porous heat sink elementis received in the chamber for absorbing the fuel vapor admitted throughthe inlet. The porous heat sink element is in conductive thermal contactwith the thermoelectric element.

According to another aspect, a microcondenser device for an evaporativeemission control system includes a housing having an inlet for receivingfuel vapor and a condensation outlet for discharging condensed fuelvapor. A porous heat sink element is disposed in the housing and fluidlyinterposed between the inlet and the condensation outlet for absorbingthe fuel vapor received through the inlet. A thermoelectric element isin thermal contact with the thermal heat sink element for removing heatfrom the fuel vapor absorbed by the porous heat sink element to condensethe fuel vapor. At least one support baffle supports the porous heatsink element within the housing.

According to a further aspect, a microcondenser device for anevaporative emission control system includes a housing having an inletfor receiving fuel vapor and a condensation outlet for dischargingcondensed fuel vapor. A porous heat sink element is disposed in thehousing and is fluidly interposed between the inlet and the condensationoutlet for absorbing the fuel vapor received through the inlet. Athermoelectric element is in thermal contact with the porous heat sinkelement for removing heat from the fuel vapor absorbed by the porousheat sink element to condense the fuel vapor. A heat removal assembly isin conductive thermal contact with a hot side of the microcondenserelement for removing heat therefrom. The heat removal assembly comprisesat least one of: a heat pipe or a liquid cooling circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an evaporative emission control systemhaving a microcondenser device for processing fuel vapor.

FIG. 2 is a perspective view, partially in cross-section, of themicrocondenser device.

FIG. 3 is an elevational cross-section view of the microcondenserdevice.

FIG. 4 is plan cross-section view of the microcondenser device.

FIG. 5 is an elevational cross-section view of a microcondenser deviceaccording to an alternate embodiment.

FIG. 6 is a plan cross-section view of the microcondenser device of FIG.5.

FIG. 7 is an elevational cross-section view of a microcondenser deviceaccording to another alternate embodiment.

FIG. 8 is a plan cross-section view of the microcondenser device of FIG.7.

FIG. 9 is an elevational cross-section view of a microcondenser deviceaccording to yet another alternate embodiment.

FIG. 10 is a plan cross-section view of the microcondenser device ofFIG. 9.

FIG. 11 is a schematic elevational view of a microcondenser devicehaving a heat pipe (shown in cross-section) for removing heat therefrom.

FIG. 12 is a schematic elevational view of a microcondenser devicehaving a cooling fluid circuit for removing heat therefrom.

DETAILED DESCRIPTION

Referring now to the drawings wherein the showings are for purposes ofillustrating one or more exemplary embodiments and not for purposes oflimiting same, FIG. 1 schematically shows an evaporative emissioncontrol system 10 for an internal combustion engine 12. As shown, theengine 12 is provided with an induction system including an intake pipe14 in which a throttle valve 16 is operatively mounted. A throttle valveopening (THA) sensor 18 is connected to the throttle valve 16. Thethrottle valve opening sensor 18 outputs a signal corresponding to theopening angle (THA) of the throttle valve 16 and supplies the signal toan electronic control unit (ECU) 20. Fuel injection valve 22, only oneof which is shown, are inserted into the intake pipe 14 at locationsintermediate between the cylinder block of the engine 12 and thethrottle valve 16 and slightly upstream of the respective intake valves(not shown). The fuel injection valves 22 can be connected through afuel supply pipe 24 to a fuel tank 26 and a fuel pump unit 28 isprovided therealong for delivering fuel from the tank 26 to the fuelinjection valves 22. Each fuel injection valve 22 can be electricallyconnected to the ECU 20, and its valve opening can be controlled by asignal from the ECU 20.

One or more sensors can be provided on the intake pipe 14 for monitoringconditions at the intake pipe. For example, the intake pipe 14 can beprovided with an intake pipe absolute pressure (PBA) sensor 34 fordetecting an absolute pressure (PBA) in the intake pipe 14 and an intakeair temperature (TA) sensor 36 for detecting an air temperature (TA) inthe intake pipe 14 at positions downstream of the throttle valve 16.These sensors, including sensors 34, 36, can each output a signalcorresponding to a sensed condition (e.g., PBA or TA) and supply theoutputted signal to the ECU 20. In addition, the fuel tank 26 can beprovided with one or more sensors for monitoring specific conditionsassociated therewith, including, for example, a tank pressure (PTANK)sensor 38 for detecting a pressure (PTANK) in the fuel tank, a fueltemperature (TGAS) sensor 40 for detecting a fuel temperature (TGAS) inthe fuel tank 26, and a fuel level sensor 42 for detecting a fuel level(i.e., a remaining fuel amount) in the fuel tank 26. Like the othersensors described herein, the fuel tank sensors, including sensors 38,40, 42, can each output a signal corresponding to a sensed condition atthe fuel tank 26 and provide the signal to the ECU 20.

Additional sensors can be provided on or in association with the engine12. More particularly, an engine rotational (NE) sensor 44 for detectingan engine rotational speed (NE) can be disposed near the outer peripheryof a camshaft or crankshaft (both not shown) of the engine 12. There canalso be provided an engine coolant temperature sensor 46 for detecting acoolant temperature (TW) of the engine 12 and an oxygen concentrationsensor (also referred to as a “LAF sensor”) 48 for detecting an oxygenconcentration in exhaust gases from the engine 12. Detection signalsfrom these sensors 44, 46, 48 can be supplied to the ECU 20. The LAFsensor 48 can function as a wide-area air-fuel ratio sensor adapted tooutput a signal substantially proportional to an oxygen concentrationand exhaust gases (i.e., proportional to an air-fuel ratio of air-fuelmixture supplied to the engine 12).

The evaporative emission control system 10 further includes amicrocondenser device 50. With additional reference to FIG. 2, themicrocondenser device 50 includes a housing 52 having an inlet 54 forreceiving fuel vapor and a condensation outlet 56 for dischargingcondensed fuel vapor. In the illustrated embodiment, the inlet 54 isconnected to the fuel tank 26 through vapor line 58 so that fuel vaporsformed in the fuel tank 26 can be delivered to the microcondenser device50. The condensation outlet 56 is also connected to the fuel tank 26. Inparticular, the condensation outlet 56 is connected to the fuel tank 26through condensation discharge line 60 for directing condensed vapor(i.e., liquid fuel) from the microcondenser device back to the fuel tank26. The housing 52 can also have a vapor outlet 62 for discharging fuelvapor that remains vaporized after passing through the microcondenserdevice 50. In the illustrated embodiment, the vapor outlet 62 is fluidlyconnected to the intake pipe 14 upstream of the fuel injectors 22 viavapor line 64. This allows fuel vapor discharged by the microcondenserdevice 50 to be recirculated through the internal combustion engine 12for combustion therein.

As will be described in more detail below, the microcondenser device 50can also include a thermoelectric element 66 for condensing fuel vaporsadmitted through the inlet 54. The thermoelectric element 66 can be aPeltier microelement that employs or uses the Peltier effect to condenseevaporative or vaporized fuel received from the fuel tank 26 via thevapor line 58. Advantageously, providing the thermoelectric element 66as a Peltier microelement can be effective for condensing vaporized fuelfrom the fuel tank 26 while being of a small size and requiring minimumpower consumption thereby not taxing the spatial layout of the vehicleor its electrical system. Operation of the microcondenser device 50 canoccur as described in U.S. Pat. No. 7,527,045, which is expresslyincorporated in its entirety herein.

With additional reference to FIGS. 3 and 4, the housing 52 has a bottomor lower wall 70 and at least one side wall 72, 74, 76, 78 extendingupward from the lower wall 70. The lower wall 70 and the at least oneside wall 72-78 together define a chamber 80 in the housing 52. In theembodiment illustrated in FIGS. 2-4, the housing 52 has a cuboid orbox-shaped configuration such that the at least one side wall includesfour rectangular side walls 72, 74, 76, 78, each extending orthogonallyupward from the lower wall 70. As shown, the inlet 54 is defined in thehousing 52, and particularly the side wall 76 thereof, for admittingfuel vapor into the chamber 80. The condensation outlet 56 is defined inthe housing 52, and particularly in the side wall 72 thereof, fordischarging liquid fuel that is condensed from the fuel vapor in thechamber 80. The vapor outlet 62 is defined in the housing 52, andparticularly in the side wall 78 thereof, for discharging uncondensedfuel vapor from the chamber 80.

The thermoelectric element 66 is supported by the at least one side wall(i.e., side walls 72-78 in the embodiment illustrated in FIGS. 2-4) inspaced relation relative to the lower wall 70. By this arrangement, thethermoelectric element 66 is spaced apart vertically from the bottomwall 70. For supporting the thermoelectric element 66 in spaced relationrelative to the lower wall 70, the at least one side wall (i.e., sidewalls 72-78) can include a recess 82 defined by a shoulder 84 and face86 extending upward from the shoulder 84. In particular, each of theside walls 72-78 of the illustrated embodiment can include shoulder 84and face 86 defining the recess 82. As shown, the thermoelectric element66 can be supported on the shoulder 84 and sized such that at least oneperipheral edge of the thermoelectric element 66 is positioned closelyadjacent the face 86. In the illustrated embodiment, the thermoelectricelement 66 can have a rectangular configuration including fourperipheral edges 66 a and each peripheral edge 66 a can be positionedclosely adjacent face 86 of a corresponding one of the side walls 72-78.By this arrangement, the thermoelectric element 66 is nestably receivedwithin the recess 82 defined in the housing 52.

A porous heat sink element 100 can be disposed in the housing 52, andparticularly received in the chamber 80 of the housing 52. The porousheat sink element is fluidly interposed between the inlet 54 and thecondensation outlet 56 for absorbing the fuel vapor received or admittedthrough the inlet 54. The thermoelectric element 66 can be in thermalcontact with the porous heat sink element 100 for removing heat from thefuel vapor absorbed by the porous heat sink element 100 to condense thefuel vapor. In particular, the porous heat sink element 100 can be inconductive thermal contact with the thermoelectric element 66. Inaddition to be interposed between the inlet 54 and the condensationoutlet 56, the porous heat sink element 100 is also fluidly interposedbetween the inlet 54 and the vapor outlet 62, which discharges fuelvapor that remains vaporized after passing through the porous heat sink100.

In one embodiment, the porous heat sink element 100 is a carbon foamheat sink element. Being formed of carbon foam provides advantages suchas higher thermal conductivity and greater surface area per unit volumethan conventional heat sinks and/or heat sinks formed of aluminum fins.Moreover, the carbon foam heat sink element 100 has greater heattransfer efficiency than conventional arrangements which results in theoverall electric load needed to power the microcondenser device 50 beingconsiderably lower than would be necessary if the heat sink were formedwith conventional fins.

In the illustrated embodiment, a copper plate 102 is interposed betweenthe porous heat sink element 100 and the thermoelectric element 66.Accordingly, conductive heat transfer occurs from the porous heat sinkelement 100, then to the copper plate 102, and next to thethermoelectric element 66. Using the copper plate 102 allows forimproved heat transfer from the porous heat sink element 100 to thethermoelectric element 66. In particular, the copper plate 102 can havean improved flatness, particularly on a side 104 that interfaces withthe porous heat sink element 100 (i.e., improved flatness compared toother efficient heat transfer materials). In addition, a thermal paste106 can be interposed between at least one of the copper plate 102 andthe thermoelectric element 66 or the copper plate 102 and the porousheat sink element 100. In the illustrated embodiment, as shown, thermalpaste 106 is interposed between both the copper plates 102 and thethermoelectric element 66 and the copper plate 102 and the porous heatsink element 100. The thermal paste 106 facilitates better heat transferbetween conductive elements of the microcondenser device 50.

As shown in the illustrated embodiment, the copper plate 102 issupported by the shoulder 84 and the thermoelectric element 66 issupported on top of the copper plate 102. Together, the thermoelectricelement 66 and the copper plate 102 are nestably received within therecess 82 defined in the housing 52. Particularly, in the illustratedembodiment, these elements 66, 102 form an upper side of the housing 52and close the chamber 80 defined by the housing 52. A seal 108 can beinterposed between the underside 104 of the copper plate 102 and theshoulder 84 defined in each of the side walls 72-78. The nestingrelation of the copper plate 102 and the thermoelectric element 66within the recess 82 and/or the provision of the seal 108 is believed toadvantageously reduce or eliminate frost or fog formation on themicrocondenser device 50, and particularly the housing 52 thereof, whichimproves efficiency of the device 50 (i.e., less power is needed tooperate the device). [Question for inventors: what material is the seal108 formed of?]

Also to improve efficiency of the microcondenser device 50, the housing52 can be formed of a plastic material. This provides the housing 52with a low heat mass body and a low thermal conductivity body material.The particular plastic material employed for the housing 52 can havesufficient rigidity while otherwise reducing the amount of energy neededfor the thermoelectric element 66 to cool vaporized fuel passing throughthe porous heat sink element 100. Using plastic also provides anadditional minimal weight benefit through the use of a lighter material.

Specifically, for example, the body material of the housing 52 can bepolyamide, polyacetal, PEI, PPS, or any other fuel-resistant plasticmaterial providing for low heat loss and/or low thermal mass. Inaddition, to further limit thermal loss to the environment, aninsulation or an insulating layer can be disposed one of: around anexterior of the housing 52 or inside the housing around the porous heatsink element 100. In the illustrated embodiment, a foam insulating layer110 is shown provided around an exterior of the housing 52.Alternatively, other insulating materials can be applied to the exteriorof the housing 52. For example, aerogels or other foams can be appliedto an exterior of the housing for insulating the housing from thermallosses to the surrounding environment.

The microcondenser device 50 can additionally include at least onesupport baffle supporting the porous heat sink element 100 within thehousing 52. As will be described in more detail below, the at least onesupport baffle supports the porous heat sink element 100 in an elevatedposition (i.e., in spaced apart relation) from the lower wall 70 and inconductive thermal contact with the thermoelectric element 66. As willalso be described in more detail below, the at least one support bafflecan urge the porous heat sink element 100 toward the thermoelectricelement 66 and/or into thermal contact with the thermoelectric element66. The at least one support baffle can be one or more baffles shaped orconfigured to provide various sub-chambers within the chamber 80 of thehousing 52. The baffles can be formed of a foam insulation material,such as a Teflon foam insulation, for example, which provides thebaffles with some resiliency and enable the stacked baffles to urge theporous heat sink element 100 toward the copper plate 102, which assistsin efficient heat transfer therebetween.

In the illustrated embodiment, the at least one support baffle includesa plurality of stacked baffles, which facilitates the baffles urging orsupplying support pressure against the porous heat sink element 100.Whether stacked, shaped or otherwise configured, the one or more supportbaffles can be arranged to efficiently direct fuel vapor into the porousheat sink element 100 and/or to facilitate efficient liquid drainage(i.e., condensed fuel vapor). In the illustrated embodiment, theplurality of baffles includes a base baffle 112 having a cut out orrecess 114 accommodating the condensation outlet 56. Intermediatebaffles 116, 118, 120, 122 are stacked on the base baffle 112. Inparticular, intermediate baffles 116, 118 are together stacked and forma first pair of stacked baffles. Likewise, intermediate baffles 120, 122are together stacked and form a second pair of stacked baffles. Thus,the baffles 116-122 are arranged in stacked pairs wherein the first pairof stacked baffles 116, 118 are together stacked adjacent the inlet 54and the second pair of baffles 120, 122 are stacked adjacent the vaporoutlet 62, and wherein the pairs of stacked baffles 116, 118 and 120,122 flank the condensation outlet 56.

The baffles can be arranged so as to direct gas and/or liquid flowwithin the microcondenser device 50 and support the porous heat sinkelement 100. For example, upper baffles 124, 126 are disposed in stackedrelation above the intermediate baffles 116-122 and can directly supportthe porous heat sink element 100. In particular, the illustratedembodiment, the upper baffle 124 is stacked on the first pair ofintermediate baffles 116, 118 adjacent the vapor inlet 54 and the upperbaffle 126 is stacked on the second pair of intermediate baffles 120,122 adjacent the vapor outlet 62. Like the intermediate baffles 116-122,the upper baffles 124, 126 can be laterally spaced apart from oneanother to flank the condensation outlet 56.

In the illustrated embodiment of FIGS. 2-4, the baffles are arranged soas to define a plenum chamber 128 adjacent the vapor inlet 54 andextending from the side wall 72 to the side wall 74. The plenum chamber128 can allow the fuel vapor admitted through the vapor inlet 54 toexpand along a dimension of the porous heat sink element 100 extendingfrom the side wall 72 to the side wall 74 and thus more effectivelyabsorb the fuel vapor. In particular, the plenum chamber 128 of theillustrated embodiment is formed by the side walls 72, 74, 76, thebaffles 118 and 124, and the porous heat sink element 100. The plenumchamber 128 extends along substantially an entire width of the porousheat sink element 100 (e.g., the width extending between the side walls72, 74). The plenum chamber 128 can function to ensure that fuel vaporentering through the inlet 54 is allowed to spread out before beingabsorbed into the porous heat sink element 100.

The baffles also define a condensation chamber 130 vertically betweenthe condensation outlet 56 and the porous heat sink element 100. Asshown, the condensation chamber 130 is disposed below the porous heatsink element 100. This allows gravity to assist in removing condensedfuel from the porous heat sink element 100 and directing the same to thecondensation outlet 56. The upper baffle 124 is smaller in theillustrated embodiment that the upper baffle 126, which defines anexpanded area 132 of the condensation chamber 130. The expanded area 132facilitates gravitational removal of condensed fuel from the porous heatsink element 100 on a side of the condensation chamber 130 adjacent thevapor inlet 54. [is this correct?]

With reference to FIGS. 5 and 6, a microcondenser device 150 isillustrated. The microcondenser device 150 can be the same as themicrocondenser device 50 except as indicated below. In FIGS. 5 and 6,the base and intermediate stacked baffles of the microcondenser device50 are replaced with a single shaped baffle 152 that includes a baseportion 154 similar in configuration to the base baffle 112 andintermediate baffle portions 156, 158 that are similar in configurationto the stacked intermediate baffles 116-122. The microcondenser device150 includes upper baffles 160, 162 disposed in stacked relation on theintermediate baffle portions 156, 158. Unlike the microcondenser device50, the microcondenser 150 has its upper baffles 160, 162 sized andarranged to provide varying shapes for plenum chamber 164 andcondensation chamber 166. In particular, the upper baffle 160 has a rearside 168 aligned with a rear side 170 of the intermediate baffle portion156. Accordingly, no expanded area 132 is defined above the intermediatebaffle portion 156; however, the plenum chamber 164 has an increaseddepth (i.e., a dimension from the vapor inlet 54 and/or side wall 76 tothe upper baffle 160). Instead of the expanded area 132, an expandedarea 172 is disposed above the intermediate baffle portion 158. Theexpanded area 172 results from the rear edge 174 of the upper baffle 162being laterally spaced apart from the rear side 176 of the intermediatebaffle portion 158.

With reference to FIGS. 7 and 8, another microcondenser device 250 isillustrated. The microcondenser device 250 can be the same as themicrocondenser device 150 except as indicated below. In the embodimentillustrated in FIGS. 7 and 8, the upper baffle 162 is replaced withupper baffle 126 (i.e. the same baffle used in the microcondenser device50). Accordingly, in this embodiment, there is no expanded area of thecondensation chamber 130 above the intermediate baffle portion 156 orabove the intermediate baffle portion 158, only the enlarged plenumchamber 164.

With reference to FIGS. 9 and 10, still another microcondenser device350 is illustrated, which can be the same as the microcondenser device150 except as indicated below. In the microcondenser device 350, upperbaffle 124 (same as used in the microcondenser 50) is disposed above theintermediate baffle portion 156 and the upper baffle portion 162 isdisposed above the intermediate baffle portion 158. Accordingly, by thisarrangement, expanded area 132 is disposed above the intermediate baffleportion 156 and expanded area 172 is disposed above the intermediatebaffle portion 158. A small plenum chamber 128 is also disposed abovethe intermediate baffle portion 156 adjacent the inlet 54.

Returning reference to FIGS. 2-4, the porous heat sink element 100 canhave a varying porosity. One exemplary varying porosity for the porousheat sink element 100 is schematically illustrated by the stippling inthe figures. As shown, the porous heat sink element 100 can have anincreased porosity at a first side or portion 100 a, which is adjacentthe plenum chamber 128 and the inlet 54, than adjacent a second side orportion 100 b. The porous heat sink element 100 can also have anincreased porosity adjacent an underside or underside portion 100 c thanan upper side or upper side portion 100 d that is adjacent thethermoelectric element 66. While the illustrated embodiment includesprogressively decreasing porosity from the first side portion 100 a tothe second side portion 100 b and from the underside portion 100 c tothe upper side portion 100 d, it is to be appreciated that such varyingporosity could occur only from one side to another (e.g., from sideportion 100 a to side portion 100 b or from side portion 100 c to sideportion 100 d). Alternatively, other arrangements or patterns of varyingporosity could be used with the heat sink element 100.

As best shown in FIG. 3, the arrangement of the vapor inlet 54 and theoutlets 56, 62 relative to one another can facilitate efficient vaporflow and liquid flow through the microcondenser device 50. As usedherein, relative positioning can refer to positioning of a central axisor central area of each of the inlet 54 and outlets 56, 62 relative toone another. In particular, as shown, the vapor outlet 62 can berelatively positioned vertically above the vapor inlet 54 and above thecondensation outlet 56. The condensation outlet 56 can be relativelypositioned below the vapor inlet 54 and below the vapor outlet 62. Thevapor inlet 54 can be disposed vertically between the vapor outlet 62and the condensation outlet 56. In addition to relative positioning,relative sizing can facilitate efficient fuel flow through themicrocondenser device 50. For example, as shown, the vapor inlet 54 canhave an increased size relative to the condensation outlet 56, whichitself can have an increased size relative to the vapor outlet 62.

With reference to FIGS. 11 and 12, the microcondenser device 50 canadditionally include a heat removal assembly 170 or 172 that is inthermal contact with a hot side 66 b of the thermoelectric element 66.The heat removal assembly 170 or 172 can comprise at least one of heatpipe 170 (FIG. 11) or a liquid cooling circuit 172 (FIG. 12). In FIG.11, an exemplary heat pipe 170 is shown having a casing 174, a wick 176and a vapor cavity 178. As is known and understood by those skilled inthe art, the heat pipe 170 can facilitate more rapid removal of heatfrom the hot side 66 b of the thermoelectric element 66, which reducesthe power consumption of the thermoelectric element for condensing fuelvapor in the cavity 80. In FIG. 12, an exemplary liquid cooling circuit172 is shown having a pump 180, a heat exchanger 182 and a liquidcirculation loop 184. As is known and understood by those skilled in theart, the pump 180 circulates a heat transfer fluid (e.g., antifreeze) inthe loop 184 from the hot side 66 b of the thermoelectric element 66where the fluid absorbs heat from the thermoelectric element 66 to theheat exchanger 182 where the fluid dissipates its absorbed heat.Alternatively or in addition, the hot side 66 a of the thermoelectricelement 66 can be cooled by convection fins and/or a fan (both notshown). Although not shown, a thermal paste can be used between the heatremoval assembly 170 or 172 and the hot side 66 a of the thermoelectricelement 66. Using the heat pipe 170 or the liquid cooling circuit 172,rapid heat removal can occur from the hot side 66 a of thethermoelectric element 66 increasing its efficiency.

Advantageously, the microcondenser devices described herein can provideimproved efficiencies which allow the devices to have smaller footprintswhen employed in a vehicle electrical system. It will be appreciatedthat various of the above-disclosed and other features and functions, oralternatives or varieties thereof, may be desirably combined into manyother different systems or applications. Also that various presentlyunforeseen or unanticipated alternatives, modifications, variations orimprovements therein may be subsequently made by those skilled in theart which are also intended to be encompassed by the following claims.

1. A microcondenser device for an evaporative emission control systemassociated with an internal combustion engine, comprising: a housinghaving a lower wall and at least one side wall extending upward from thelower wall, the lower wall and the at least one side wall togetherdefine a chamber in the housing; a thermoelectric element supported bythe at least one side wall in spaced relation relative to the lowerwall; an inlet defined in the housing for admitting fuel vapor into thechamber; a condensation outlet defined in the housing for dischargingliquid fuel that is condensed from the fuel vapor in the chamber; and aporous heat sink element received in the chamber for absorbing the fuelvapor admitted through the inlet, the porous heat sink element inconductive thermal contact with the thermoelectric element.
 2. Themicrocondenser device of claim 1 further including at least one supportbaffle supporting the porous heat sink element in an elevated positionfrom the lower wall and in conductive thermal contact with thethermoelectric element.
 3. The microcondenser device of claim 1 whereinthe porous heat sink element is a carbon foam element having a varyingporosity.
 4. The microcondenser device of claim 1 further including avapor outlet defined in the housing for discharging uncondensed fuelvapor, the vapor outlet elevated relative to the inlet and the inletelevated relative to the condensation outlet.
 5. The microcondenserdevice of claim 1 further including a heat pipe or a liquid coolingcircuit for removing heat from the thermoelectric element.
 6. Amicrocondenser device for an evaporative emission control system,comprising: a housing having an inlet for receiving fuel vapor and acondensation outlet for discharging condensed fuel vapor; a porous heatsink element disposed in the housing and fluidly interposed between theinlet and the condensation outlet for absorbing the fuel vapor receivedthrough the inlet; a thermoelectric element in thermal contact with theporous heat sink element for removing heat from the fuel vapor absorbedby the porous heat sink element to condense the fuel vapor; and at leastone support baffle supporting the porous heat sink element within thehousing.
 7. The microcondenser device of claim 6 wherein the porous heatsink element is a carbon foam heat sink element.
 8. The microcondenserdevice of claim 6 wherein the housing has a vapor outlet for dischargingfuel vapor that remains vaporized after passing through the porous heatsink element, the porous heat sink element fluidly interposed betweenthe inlet and the vapor outlet.
 9. The microcondenser device of claim 8wherein the housing includes a bottom wall and at least one side wallextending upward from the bottom wall, the thermoelectric element isspaced apart vertically from the bottom wall, the at least one supportbaffle supports the porous heat sink element in spaced apart relationfrom the bottom wall.
 10. The microcondenser device of claim 9 whereinthe at least one support baffle urges the porous heat sink elementtoward the thermoelectric element.
 11. The microcondenser device ofclaim 9 wherein the at least one support baffle urges the porous heatsink element into thermal contact with the thermoelectric element. 12.The microcondenser device of claim 9 wherein a plenum chamber is formedby the at least one side wall, the at least one support baffle and theporous heat sink element, the plenum chamber extending alongsubstantially an entire width of the porous heat sink element.
 13. Themicrocondenser device of claim 12 wherein the porous heat sink elementhas an increased porosity adjacent the plenum chamber.
 14. Themicrocondenser device of claim 9 wherein the porous heat sink elementhas an increased porosity adjacent a first side of the porous heat sinkelement disposed adjacent the inlet than a second side adjacent thevapor outlet.
 15. The microcondenser device of claim 14 wherein theporous heat sink element has an increased porosity adjacent an undersideof the porous heat sink element disposed adjacent the condensationoutlet than an upper side adjacent the thermoelectric element.
 16. Themicrocondenser device of claim 9 wherein the porous heat sink elementhas an increased porosity adjacent an underside of the porous heat sinkelement disposed adjacent the condensation outlet than an upper sideadjacent the thermoelectric element.
 17. The microcondenser device ofclaim 6 wherein the thermoelectric element is nestably received within arecess defined in the housing.
 18. The microcondenser device of claim 17wherein the housing includes a bottom wall and at least one side wallextending upward from the bottom wall, the at least one side wallincludes a recess defined by a shoulder and face extending upward fromthe shoulder, the thermoelectric element supported on the shoulder andsized such that at least one peripheral edge of the thermoelectricelement is positioned closely adjacent the face.
 19. The microcondenserdevice of claim 18 wherein a copper plate is interposed between theporous heat sink element and the thermoelectric element.
 20. Themicrocondenser device of claim 1 wherein a copper plate is interposedbetween the porous heat sink element and the thermoelectric element. 21.The microcondenser device of claim 20 wherein a thermal paste isinterposed between at least one of: the copper plate and thethermoelectric element or the copper plate and the porous heat sinkelement.
 22. The microcondenser device of claim 6 wherein the porousheat sink element has an increased porosity adjacent the inlet thanadjacent the condensation outlet.
 23. The microcondenser device of claim6 wherein the housing is formed of a plastic material.
 24. Themicrocondenser device of claim 6 wherein an insulating layer is disposedone of: around an exterior of the housing or inside the housing aroundthe porous heat sink element.
 25. The microcondenser of claim 6 furtherincluding a heat removal assembly for removing heat from a hot side ofthe microcondenser element, the heat removal assembly comprising atleast one of: a heat pipe or a liquid cooling circuit.
 26. Amicrocondenser device for an evaporative emission control system,comprising: a housing having an inlet for receiving fuel vapor and acondensation outlet for discharging condensed fuel vapor; a porous heatsink element disposed in the housing and fluidly interposed between theinlet and the condensation outlet for absorbing the fuel vapor receivedthrough the inlet; a thermoelectric element in thermal contact with theporous heat sink element for removing heat from the fuel vapor absorbedby the porous heat sink element to condense the fuel vapor; and a heatremoval assembly in conductive thermal contact with a hot side of themicrocondenser element for removing heat therefrom, the heat removalassembly comprising at least one of: a heat pipe or a liquid coolingcircuit.